Method of manufacturing starch



Oct. 20, 1931. R. o. MccoY ET AL 1,828,334y u* METHOD OF MANUFACTURING STARCH Filed July 25, 1929 L Nw@ RUSH o.` MccoY, or BERwYN, A Nn -oTTo A( sJosTnoM, or cHroAGo, ILLINoIs, AssIGNoRs To INTERNATIONAL PATENTS DEVELOPMENT COMPANY, or wILMINGToN,

Patented Oct. 20,r 1931 i UNITED STATES PATENT `ovl-FICE DELAWARE, .Ad CORPORATION OF DELAWARE OF MANUFACTURING STARCH This invention relates to themanufacture of starch by a process of the type involving,

the reuse in the system, repeatedly, of gluten Water, that is, liquid from the starch tables,

. washed with fresh water, this-operation re-` I ably afterfthejbulk of the gluten which it carand the filtrates from the dehydrating and washing operations to which the starch taken from the starch tables is'subjected for the purpose of removing soluble 'substances from the starch; the purpose of reusing these waste waters being to prevent stream pollution, save solidY substances otherwise. wasted and decrease the amount of water req lred for the separating and washing operati ns.

According to the present methods of making starch, particularly starch Jfrom Indian corn, the starch bearing materiahthe corn for example, .after being steeped in warm Water containing sulphurous acid (steeping system) is broken up and-the germ Separated from the rest of the material and washed (germ system); the rest of the material is nely ground and subjected to separatin-g operations with water, containing sulphurous acid, in copper reels or on copper shaking screens to remove the coarser bran and fibre particles (coarse slop system) the liquid magma from the coarse slop system is subjected to .a series of separating operations in silk reels or on silk shakers to remove the finer particles of bran and fibre (fine slop system); the liquid Y from the germ and lcoarse and fine slop systems is run over form cakes or layers and the cakes or layers moving Jfrom` the starch the soluble substances therein, at least to a large extent, and any other impurities which the starch may contain. l s

The waterA from Jthe'starch tables, prefer-- ries has'been removed by settling in the glutensettlers (gluten water) and thelwater derived :trom/the starch filtering operations,

that-is, from the dehydrating of the starch i (first filtrate) and the subsequent Washing of the starch cake or layer (second filtrate) is returned to the process for use inI steeping the grain, in the mills for comminuting the grain and in the germ, coarse slop and ne slop systems; the milling and separating operations just mentioned constituting collectively what has been known as the wet starch system.

It" has been customary to give the tabled starch successive filtering operations in dehydgating and washing filters, returning the more concentrated iltrates to the wet starch 'y system and employing the filtrates lighter in solubles for flushing the starch from the tables, thereby eii'ecting a water balance in the system so that no substantialportion of any of the used liquors are sent to the sewer. See United States patent, Rush O. McCoy, N o. 1,651,611, December 6, 1927.

It has also been the practice to control the amount of sulphurous-acid entering the wet starch system with the corn from the steeping system by washing the steeped corn with returnedv gluten water, and to reuse gluten water inthe germ and coarse slop systems and the iiltrates from the starch washing operation in the fine slop system. See United States'patent, G, M. Moi/fett, No. 1,655,395, Jan. 3, 1928.

It has long been customary to introduce sulphurous acid at various points, into the processes following the steeping of the grain, in addition tousing the acid, in larger quantities, in the steeping system, the purpose being to check the growth of micro-organisms. It'has also beenvcustomary to heat the liquids in process to whatever temperatures were deemed desirable for insuring proper drainage especially through the silk.

It may be said that improper drainage through the silk reels or shakers (whether those of the fine slop system or the silk screening devices used for clean-up purposes may coderma yeast, which clogging may be f of a much more serious nature. It is due to the formation of a slimy filamentous growth which adheres firmly to thev silk fibers and `cannot be effectively removed by the treatl n malvlncrustatlon.`

ments that areV suiicient as against the nor- It has now been discoveredxthat this slimy growth is due to fungi organisms belonging fad to or related to the oidium. groups of fungl, theI owth of which is possible only when the 62 concentrations in the system are relatively low. l

0n the basis of this discovery the present invention provides for an improveddistribution of the returned liquids, facilitating the control `of the process and making possible the use of smaller quantities of SO2' whereby a saving of sulphur is eii'ected and the incon' veniences such as offensive smells in the factory, corrosion of metals and presence o f metallic salts in the starch are avoided.

In accordance with the present invention the gluten water is reused primarily in the fine slop system, the eXcess,-if any, going to the coarse slop or to the germ system or to both. The liltrates from the starch washing operations are returned to the germ and coarse slop systems. The gluten water, with a normal or even somewhat lower than normahamou'nt of SO2 in the system, will contain enough SOzfso that it can be used advantageously for increasing the SO2 content at the'latter end of the wet starch systemthe fine slop reels or shakers--where the SO2 introduced with the steeped corn approaches depletion. Now, experience has shown that when gluten water is returned to the fine slop system, wlth its normal amount of SO2, the

. process remains normal and no disturbances are experienced with sliming of the silks as mentloned 1n the second case of clogging. The use of gluten water at this point must ftherefore-be considered beneficial and advantageous to the efficiency ofthe silk reels and shakers. This effect is due in part at least, and perhaps rimarily, to the residual SO2 1n the liquid utl it may be due perhaps in some measure also, to other factors such as the presence` in the glutenwater of products of micro-organic activity tending to inhibit the growth of the slime forming'organisns.'

Whether this be so or not it seems to be the fact that the gluten water, in reference to sliming in the wet starch process, is a disinfecting, not a'n infectingagent.-

The object of this invention is to take advantage of the discoveries indicated by utilizingrgluten water for the separations carried on in the fine slop system.

The invention is illustrated in a preferred embodiment in the annexed llow sheet drawing in which theshowing of tha apparatus` is simplified to the extent that single Iunits only are illustrated in place of the multiplicity of units that would ordinarily beemployed in a commercial plant. The drawin also omits pumps, control valves and the like which it is to be understood are used where required.

The process of the present invention will now be described in detail, reference being made to the accompanying drawing.

Szfeepz'ng system.-The steeping system, consisting ofy a battery of steep tanks designated A-1 to A- -l1, is the same as described in Patent No. 1,655,395 above referred to and it will be suiicient to state that A-l represents the steep tank from which the steeped and washed corn is being withdrawn for grinding; A-2, A-3, the tanks in which the steeped corn is being washed to reduce its SO2 content before the corn is sent to the wet starch system, this step being optional depending upon the SO2 concentrations in the steeps and those desired to be maintained at the irst separators; A-4 to A-10 the tanks in which the corn is being steeped; and A-ll the one which is filling with fresh corn; C-l designating the sulphur tower for charging the gluten water from tanks A-2, A-3 with vSO2 before the water enters the first steeping tank A-4,` so as to maintain the SO2 concentration in the steeps at the desired point, for example, 0.3%, based yon the usual iodine titration method of computing SO2. A pipe 24, containing heater L-l, brings the returned gluten water to tank A-2. The concentrated steep water from A`10 is discharged to the evaporator (not shown) through a pipe (outlet a).

Gem systemf-The steeped corn dis- @charged from tank A-l, through pipe to the mill B-l, is there broken up and the germ freed. The material then goes through pipe 26 to separator D-l in which the germs are separated from the grits and hulls by notation. The germs floating ofi' are passed through pipe 27 into germlreel E-l, then through pipe 28 to reel E-2, pipe 29 to reel E-'3, and pipe 30 to the press F--l, the germs going out of the system at this point (outlet b) and the water from the press being returned to reel E-2 through pipe 31. The liquid from reel E--3 passes by pipe 32 to meel E-2, the liquid from E-2 by pipe 33 to reel E-,l and the liquid vfrom E-l by pipe 34 lto the separator D-l. The hulls and hgrits from separator D--l pass through pipe 35 to a reel. E-5 the liquid from which goes by pipe 36 to a'separator D-2. The tailings from reel E-5 pass through a pipe 37 to mill B`-2 which discharges, by pipe 38, into the separator D-2. The germs from separator to reel E G and the starch milk (starch and' gluten) by pipe 41 to the shaker E-7, thence by a pipe 42 to the starch tables, as will be described, a portion of thisl liquid being diverted, where necessary to balance the system, through a pipe 413 to pipe 34. The tailings rom yreel E-6 and shaker E-7 pass through pipes 44, 45 to a'mill B3 in which this material is iinely ground. Coarse slop sg/sem.-The material groun inmill B-'3 passes through pipe 46 to the first reel G-l of the coarse slop system, then through pipe 47 to reel G-2, pipe-48 to reel G-3, pipe 49 to reel `'Gr-4, and pipe .5() to press F-2, the water fromthe press going back through pipe 51 to reel G--3. .The pressed coarse slop is withdrawn from the system in moist condition (outlet c). The liquid from reel G-l4 passes through pipe 52 to reel G-3; and the liquids from (3l-3 and (ir-2 pass by pipes 53, 54 to reel G-L The liquid from reel G-l passes by pipe 55 to a shaker G-5 and by pipe 56 to they starch tables. v y

Liquid for the mills, germ syste-m and coarse slop system, just described, is supplied from a storage 'tank P-l which receives iltrates from the starch .Washing system through pipe,A 57 and', through pipe 58, the excess of gluten water not used in the line slopand steeping systems. A pipe 59 leads from the tank P-l to the pipe 25, discharging into mill B-1. A branch 60 of pipe 59V connects withpipe 26 leading to separator D-L Another branch 61 connects With the pipe 38 leading to separator D-2. Another branch 62 leads to inill B-3. Another branch 63 leads to the pipe 29, discharging into the germ reel E-3 and other branches 64 and 65 lead tothe pipes 47 and 49 discharging ihtothe coarse slop reels G-2, Gr--4.v The described connections may be varied as circumstances require and the term pipes is intended tocoveil troughs or other conduits. Shakers may be used in place of reels and vice versa.

Fine slop system.-'The tailings from shaker Gr-'-5 pass by pipe 66 to shaker H-1,

i by pipe 67, to a shaker H-2; by pipe 68 to a shaker H-3 and\ by pipe 69 to a press F -3 from which the -ine slop vis discharged out of the. system (outlet-d). The Water from the -`press passes through pipe 70 to pipe 57 andVV storage tank P-l.

Liquid from reel H*3 passes by )pipe`71 to reel H-2 and liquid from reel H-2 passes by pipe 72 tou shaker H--1. The liquid from reel -H-l passes by pipe 73 to the starch tables. y

The water used for makingthe fine slop separation is gluten water from gluten settler K,-2 which enters the storage tank P--2 through pipe 74. lts SO2 content should be suHcient to prevent any possibility of sliming and can be regulated in any suitable manner. If the amount of SO2 for the steeped corn is such as to give too high an SO2 concentration in thewet starch system, the corn in the steep tanks A-2, A-43 may be washed, as described to .reduce the concentration at the rst separator D--l towhatever may be required, for example .07%. A pipe 75 conducts the gluten Water from tank P-2 to the pipe 68, which discharges into the last of the fine slop reels,J reel H-3. The pipe 75 might discharge directly into reel H-3 and the same is true of the other feed water connections throughout the system in respect to the reels or shakers which they supply.

It is possible to operate the system without lheating the gluten wat-er thus returned to the process for reuse; but in order to maintain the liquor passing through the silk reels or shakers of the fine slop system at customary temperatures and thus facilitate drainageit is desirable to warm the gluten water somewhat,'wl1ich may be done either Witha single heater or by use of a plurality of heaters as described in application of Frederick L..

Jefferies, Serial No. 304,687 filed September 8, 1928. According to the latter arrangement a heater L-3 is placed in pipe 75 and booster heaters L4 and L`5 are arranged in pipes 71 and 72. A

Taming-The pipes 42, 56 and 73, through which starch milk (starch, gluten and Water) i'sA withdrawn from the germ system, the coarse slop system and the line slop system unite in a pipe 76 leading to a clean-up shaker 141. The liquid from the clean-up shaker passes through pipe 77 to the starch table J*1. The drawing shows two tables J-l and J -2 and illustrates the depositing of the starch on J -1 and the flushing ofthe starch from J-2. The tailings, gluten and water, from the starch table J-l, pass through pipe 78 to a gluten settler K-l which is assumed to be filling. The gluten settler K-2 has already beenfilled and the gluten therein settled. The water siphoned olf from the settler K`2 (gluten water) overiows into pipe 79 from which it is distributed to the pipe 24 supplying the steeping system and to the pipe 74 leadingl to storage tank P-2,

. The starch on the starch tables (starch table J-f2) ris removed therefrom by flushing, 81 designating the flushing line and 82 the discharge pipe through which the starch passes to the Washing system when, by circulation of water through pipe 81 and over the table, the desired density has been reached.

lo Any number of filtering or washing operations `may be' employed. ,The flushed starch in `pipe 82 is preferably heated in the heater L-2 and passes to the troughv 85 of the first dehydrating and ,washing filter M-1;

1 5 Water is extracted from thev starch (first filtrate) and passes by pipe 86 to the pipe 57, leading t the starch water storagetank P-l. The layer or layers of starch on the filter are sprayed' with fresh water, preferably y2 0 warm water, introduced through the pipe 87. The wash water from the star h (second ff filtrate) passes .by pipe 88 tothe pipe 57 and starch water storage tank P-L The washed starch is then discharged, as indicated by the arrow 89, into a/dilution tank O--l into which water is introduced through pipe 90. The diluted starch passes through pipe 91 tothe trough of fthe filter M-2 Where it is vagain dehydrated, then washed, the\first o 'filtrate passing through pipe 84 to the flush- 90. The fresh water for nr un) ing line 81 above referred to, a portion being diverted, if need'be, through pipe 92 to pipe p'lied through a branch 93 of pipe 87 and the Wash Swater' is discharged from this filter into a pipe 94 leading to pipe 88. 'The starch from'filter M--2 is discharged as indicated byrarrow 95 into a dilution tank 0 2 supplied with freslfwater through pipe 96. The diluted starch in O-2 passes through pipe 97 to the trough 85 of filter M8. The firstiltrate from M-3 passes through pipe 90 to the first dilution tank 0 1. Filter M-3 is supplied with fresh water by a branch 98 of pipe 87 and the second filtrate is discharged from the filter M-3 into pipeJ 94 described as connected also with filter M2.`

The starchdischarged from filter M'-3 out- Y pipes 87 and 96 so that,'under normal con itions, it is'unnecessaryfto discharge any apprec1able amount pf water to the sewer. Y y Aconsiderablequantity of SO2 entersthe wet starch1 system with the corn, the amount being regulated by contiol ofthe washing of the corn4 in the steep tanks A-2, A-3. A certain amoilnt of SO2 enters the system at thegflushing and reaches the germ and coarse tem by use of gluten water which contains a considerable quantity of SO2. Since the amount of SO2 in the gluten water is substantially constant relative to the SO2 concentrations maintained at the separators and A at the tables, and these concentrations can be'contro'lled, the system of operation above described permits the use f of a minimum -amount of SO2, which is desirable not only in order to economize sulphur but also becausel excessive amounts of sulphurous acid Ibya method comprisingy steeping the corn inwater containing SO2 and comminuting the corn, subjecting the comminuted material in water, re eatedly reused, to germ and coarse and fine slop separations, the starch and gluten to av tabling operation and the starch from the tables to a washing op-y eration t0 remove solubles: the improvement which consists in returning for reuse gluten water containing SO2 from the starch tables tothe fine slop separation and water from 1. In themanufa'cture of starch from corny the starch washing filters to the germ and coarse slop separations. f,

2. In the manufacture of starch from corn by a method comprising steeping the corn in `Water containing SO2 and comminuting the corn, subjecting the comminuted` material in water,^ repeatedly reused, to germ4 and coarse and fine slo and gluten to a ta ling operation and the Starch from the tables to a washing operation to remove solubles: the improvement which consists in reusing heated gluten water containing SO2 from the starch tables in the fine slop separation and reusing Water from I the starch washing filters in the coarse slop separations. 3. Inthe manufacture of starch from corn by a method comprising steeping and com- -minuting the corn, subjecting the comminuted material in water, repeatedly reused, to germ and coarse and fine slop separations, the starchand gluten .to a tabling operation and the starch from the tables to a washing voperation to remove solubles: the improvement which consists in Areturning for reuse glutemwater from the starch tables to the nel slop separation and water from the starch washingl filters `to the germ and coarse slop separations, andintroducingl fresh SO2 into` the system only at the steepsand with to the washing operation. RUSH O. MCCOY. OTTO A, SJOSTRQM. A

the star'ch going separations', the starch germ and 

